1. Field of the Invention
The present invention relates to a video record/playback control apparatus capable of simultaneously recording a plurality of contents such as video decks, video servers or the like, and more particularly to preset recording control when a plurality of contents during the same time period are preset for recording and to a re-compression process for coded content data.
2. Description of the Prior Arts
The most primitive technique for recording a plurality of programs or contents broadcast during the same time period includes providing a plurality of VTRs (video tape recorders) and recording different programs with respective VTRs.
JP-A-10-243303 and JP-A-07-021619 propose preset recording control apparatuses which perform preset recording control for a plurality VTRs with a remote controller to manage schedules of which program being recorded by which VTR in order to simultaneously record a plurality of contents during the same time period. Each of VTRs in the proposals can only one content during the same time period. For this reason, in schedule management, a maximum number of contents recordable during the same time period is defined as the number of VTRs.
JP-A-09-307846 discloses a technology in which pictures are reduced in size and combined for recording on a single storage medium in tape shape and are enlarged for playback, thereby recording a plurality of contents during the same time period. In this case, a maximum number of contents recordable during the same time period can be calculated from bit rates of contents for which a VTR compresses pictures and the throughput performance of the VTR. However, a maximum number of contents recordable during the same period is known within the VTR.
Additionally, JP-A-7-107461 and JP-A-11-98478 disclose a video coding technique for re-compressing video which has been once coded and compressed. When the technique is used, video stored in a storage device is re-compressed and stored again in the storage device, thereby allowing an increase in free space in the storage device.
FIG. 24 is a block diagram showing a configuration for increasing a free space in a storage device using a conventional re-compressing method. The configuration comprises content reading unit 901 for reading out contents from storage device 904 which stores coded contents, re-compressing unit 902 for re-compressing the read coded information, and content writing unit 903 for writing re-coded data into storage device 904. In the configuration, re-compression is performed by a user specifying contents and timing for re-compression.
Presently, in various countries, shift plans are underway from conventional analog broadcast to digital broadcast for television broadcasting. In digital broadcast, video pictures are compressed and broadcast in encoding schemes for various image quality typified by HDTV (High Definition Television) or SDTV (Standard Definition Television). Since images are compressed for each content so as to match characteristics of the respective encoding schemes with characteristics of contents, bit rates of the contents to be broadcast may vary to a degree the highest one is four times or more than the lowest one.
When recording is made in such digital broadcast, image compression enables a plurality of contents to be simultaneously recorded within a range of processing capability of a record/playback control apparatus. However, since the sum of bit rates of contents to be simultaneously recorded is previously unknown in digital broadcast in which contents are sent with different bit rates, it is impossible to previously know how many contents of pictures can be simultaneously recorded. Therefore, allowing for a margin of safety, each VTR can preset for recording only one content at a time, similarly to the case disclosed JP-A-10-243303 or JP-A-07-021619.
Apparatus for recording video pictures include hard disk drives (HDDs) in addition to VTRs. The hard disk drive has a higher bit rate for reading and writing, and favorable random access characteristics as compared with VTRs. The hard disk drive can record and play back larger number of contents simultaneously. However, when a bit rate of a content is unknown previously, the bit rate of the content is assumed to be high, thereby causing a problem that the number of contents preset for simultaneous recording need be set to be in a range much lower than capability inherent in the hard disk drive.
It is an object of the present invention to provide a record/playback control apparatus capable of presetting for simultaneous recording in digital recording for digital broadcast, setting the number of contents to be preset for simultaneous recording making the most of processing capability of playback/recording, and appropriate presetting at the time when user presets recording of contents.
It is another object of the present invention to provide a program information providing apparatus for delivering program information or Electronic Programming Guides (EPG) to the aforementioned record/playback control apparatus. As to the EPG, details can be acquired on the Internet, http://www.infomedia.lu/9epg.htm
In the record/playback control apparatus of the present invention, information on bit rate of each content described in the delivered EPG is extracted, and the sum of bit rates of contents preset for simultaneous playback and recording is compared with a bit rate in processing capability of a storage device at the presetting of a recording, thereby determining whether or not the recording is possible. In other words, it is possible to determine whether a preset recording exceeds the capability of the storage device at the presetting of the recording. For this reason, a preset recording can be processed without fail.
Typically, the record/playback control apparatus according to the present invention comprises program information acquiring means for acquiring and extracting an electronic programming guide in which a bit rate of a content is described; program information storage means for storing the electronic programming guide; preset recording input means for receiving preset recording information; recording/playback preset total bit rate calculating means for calculating a total bit rate of contents preset for recording/playback at a particular time; recording/playback presetting storage means for storing recording/playback presetting; preset recording registering means for registering a new preset recording; preset recording possible/impossible display means for displaying whether a preset recording is possible or not; and preset recording possible/impossible determining means for determining whether a preset recording is possible or not using the bit rate of a content described in the electronic programming guide.
In the record/playback control apparatus of the present invention, several ways of processing are possible when an EPG can not be acquired. For example, as first processing, a preset recording is rejected when an EPG can not be acquired. With this processing, it is possible to avoid a preset recording which exceeds the processing capability of the storage device which may occur by an impossible preset recording when an EPG can not be acquired. As second processing, when an EPG can not be acquired, the bit rate of a previously stored content is handled as a bit rate of a content preset for recording, and the sum of bit rates of contents preset for simultaneous playback and recording at the time set by the preset recording is compared with the bit rate in the processing capability of the storage device, thereby determining whether or not the recording is possible. With this processing, even when an EPG can not be acquired, it is possible to determine, at the presetting of the recording, whether a preset recording exceeds the processing capability of the storage device to allow a preset recording without fail of recording.
It is preferable that whether a preset recording is possible or not is determined using, as a total bit rate, a total bit rate of contents at the maximum in the same time period as a new preset recording. In other words, when a plurality of contents have overlapping portions in recording time periods, it is preferable that a recording time period corresponding to the largest number of overlaps is used to determine whether a preset recording is possible or not. Such configuration enables settings without any lack of recording of preset contents.
In the record/playback control apparatus of the present invention, bit rate changing means is also provided for changing a bit rate of a content. The bit rate changing means can change a bit rate of at least one content such that the sum of bit rates of respective contents falls within processing capability of the record/playback control apparatus when preset recording possible/impossible determining means determines that a new preset recording is not possible. With this configuration, even when presetting of a recording is performed beyond the capability of the storage device, a total bit rate can fall within the capability of the storage device to enable settings without any lack of recording of preset contents. To achieve this, for example, it is desirable to provide re-compressing means for further compressing contents stored in the storage device.
The program information providing apparatus of the present invention is characterized in that it comprises, at least, delivery controlling means for controlling the delivery of an EPR, program information delivering means for delivering an EPG, and program information creating means for describing a bit rate of a content in an EPG, and that it delivers an EPG which has a bit rate of a content described therein using a bidirectional communication line, ground broadcasting, satellite broadcasting or a storage medium. When a bidirectional communication line is used, it is preferable to further provide delivery request receiving means for receiving a delivery request for EPG.
Specifically, the use of the program information providing apparatus of the present invention enables a bit rate of a content to be previously known in a record/playback control apparatus capable of simultaneously recording/playing back a plurality of contents which receives an EPG. As a result, whether a content is recordable or not can be determined at the presetting of the recording prior to broadcasting of the content, thereby allowing an appropriate preset recording.